The third season of the BBC mini-series 'Sherlock' featured several shockers, from the many different theories about Sherlock Holmes' death to the revelation that Mary Watson is actually a trained assassin.

The one shocking thing about Sherlock Season Three was the fact that fan favorite Irene Sadler was nowhere in sight. The character, played by Lara Pulver, did appear as a hallucination in one episode. However, fans were expecting to see more of Irene or even have the femme fatale stay as one of the main characters.

"I honestly don't know," Pulver has said about a possible Irene Adler return. "She's only in one book and Steven [Moffat] and Mark Gatiss are big Conan Doyle fans."

Show creator Steven Moffat also spoke about Irene Adler's possible comeback. "It's not impossible, because she's still alive and out there," he said. "But I was really, really pleased with [Season 2 episode] 'A Scandal in Belgravia,' and that sense of longing between those two characters. The question is, can you do it again without making it less good? Are sequels ever as good? Do you really make more money or do you debase the coinage? If we had as good a story as 'Scandal' and somewhere else to take them, we'd do it again."

Moffat also revealed that Sherlock Season Four will finally start filming in spring next year. He also hinted that the series will be "an emotional upheaval."

"[Series four] is going to be... I suppose you'd say... consequences. It's consequences. Chickens come to roost," Moffat said. "It's dark in some ways - obviously it's great fun and a Sherlock Holmes romp and all that - but there's a sense of things coming back to bite you."

'Sherlock' is a modernized take on Arthur Conan Doyle's master of deduction. The show stars Benedict Cumberbatch as Sherlock Holmes, Martin Freeman as Dr. John Watson and Gatiss as Sherlock's brother Mycroft Holmes.